The towns immediately adjacent to Casper are Mills, Evansville, and Bar Nunn.
Unincorporated areas include Allendale, Dempsey Acres, Red Buttes, Indian Springs, and several others.
The lack of a railhead doomed Bessemer in favor of Casper.
Douglas, also a railhead, survives to the present day.
The town is named "Casper", instead of "Caspar", honoring the memory of Fort Caspar and Lt.
Caspar Collins, due to a typo that occurred when the town's name was officially registered.
As of the census of 2000, there were 49,644 people, 20,343 households, and 13,141 families residing in the city.
The population density was 2,073.2 people per square mile (800.3/km²).
There were 20,343 households out of which 31.8% had children under the age of 18 living with them, 49.6% were married couples living together, 11.1% had a female householder with no husband present, and 35.4% were non-families.
The presence of a railhead made Casper the starting off point for the "invaders" in the Johnson County War.
The special chartered train carrying the men up from Texas stopped at Casper.
Lows drop to 0 °F (−17.8 °C) on 18 nights per winter. The racial makeup of the city was 92.3% White, 1.0% African American, 0.9% Native American, 0.8% Asian, 2.3% from other races, and 2.6% from two or more races.
Hispanic or Latino people of any race were 7.4% of the population.
Precipitation is greatest in spring and early summer, but even then it is not high.